As disclosed in JP 2012-005301 A (corresponding to US 2012/0001227 A1), a semiconductor device includes a semiconductor chip, terminals, and a resin portion that seals the semiconductor chip and the terminals. The terminals are projected from a surface of the resin portion toward outside, and are arranged in one direction.
In JP 2012-005301 A, the terminals of a main circuit of the semiconductor chip, which are also referred to as main terminals, are arranged on a terminal board in one direction. The terminal board has a recessed portion between two adjacent main terminals. Further, multiple control terminals are arranged on a different terminal board in one direction, and the terminal board has insulating partition walls, which have rib shapes and divide the control terminals into multiple groups.
In the above semiconductor device, the terminal boards are made of a resin material, and the recessed portions and the partition walls of the terminal boards secure a distance between two adjacent terminals. The distance needs to be secured between two adjacent terminals along a surface is also referred to as a creeping distance.
In the structure disclosed in JP 2012-005301, in order to reduce a size of the semiconductor device in the directions along which the terminals are arranged, a width of each recessed portion and a width of each partition wall need to be reduced. However, a size of each of the terminal boards, which are made of resin material and have the recessed portions and the partition walls, is difficult to be sufficiently reduced considering a strength, a withstand voltage, and a processing accuracy of the resin-made terminal board.